make installcheck failing for postgres_fdw

Hi all,

I have a server that has 9.4.4 with the postgres_fdw module successfully running for the past couple of years. I am looking to update it, so I'm testing the procedure on a test server, and have been running into trouble. Out of curiosity, I tried installing it with 10beta4, but the gmake installcheck failed. So I tried with 9.6.2 (because it happened to be on the machine) and it still failed. I tried 9.6.5--and it also failed.

I decided to try installing 9.4.4, since it hadn't failed once upon a time, and to rule out differences in OS being the cause (original server is running FreeBSD 9, test server is running FreeBSD 11), and the gmake installcheck did *not* fail for that version on my test server. Great. I repeated my procedure for 9.4.14, and that also worked. I moved on to 9.5.9, and the gmake installcheck failed again.

gmake installcheck succeeds:
9.4.4
9.4.14

gmake installcheck fails:
9.5.9
9.6.2
9.6.5
10beta4

Note that the installation doesn't seem to have any issue, just the installcheck. Is this a known issue? Is it just a matter of the regression tests lagging behind, or should I be concerned? The regression.diffs files are not identical between versions, but they only seem to contain query plans with differences.

Thank you!
Natalie

e.g.:

cat /tmp/postgresql-9.5.9/contrib/postgres_fdw/regression.diffs
*** /tmp/postgresql-9.5.9/contrib/postgres_fdw/expected/postgres_fdw.out Mon Aug 28 16:24:28 2017
--- /tmp/postgresql-9.5.9/contrib/postgres_fdw/results/postgres_fdw.out Tue Sep 19 23:36:12 2017
***************
*** 3522,3545 ****
Update on public.bar
Foreign Update on public.bar2
Remote SQL: UPDATE public.loct2 SET f2 = $2 WHERE ctid = $1
! -> Hash Join
Output: bar.f1, (bar.f2 + 100), bar.ctid, (ROW(foo.f1))
! Hash Cond: (foo.f1 = bar.f1)
! -> Append
! -> Seq Scan on public.foo
! Output: ROW(foo.f1), foo.f1
! -> Foreign Scan on public.foo2
! Output: ROW(foo2.f1), foo2.f1
! Remote SQL: SELECT f1 FROM public.loct1
! -> Seq Scan on public.foo foo_1
! Output: ROW((foo_1.f1 + 3)), (foo_1.f1 + 3)
! -> Foreign Scan on public.foo2 foo2_1
! Output: ROW((foo2_1.f1 + 3)), (foo2_1.f1 + 3)
! Remote SQL: SELECT f1 FROM public.loct1
! -> Hash
Output: bar.f1, bar.f2, bar.ctid
-> Seq Scan on public.bar
Output: bar.f1, bar.f2, bar.ctid
-> Merge Join
Output: bar2.f1, (bar2.f2 + 100), bar2.f3, bar2.ctid, (ROW(foo.f1))
Merge Cond: (bar2.f1 = foo.f1)
--- 3522,3549 ----
Update on public.bar
Foreign Update on public.bar2
Remote SQL: UPDATE public.loct2 SET f2 = $2 WHERE ctid = $1
! -> Merge Join
Output: bar.f1, (bar.f2 + 100), bar.ctid, (ROW(foo.f1))
! Merge Cond: (bar.f1 = foo.f1)
! -> Sort
Output: bar.f1, bar.f2, bar.ctid
+ Sort Key: bar.f1
-> Seq Scan on public.bar
Output: bar.f1, bar.f2, bar.ctid
+ -> Sort
+ Output: (ROW(foo.f1)), foo.f1
+ Sort Key: foo.f1
+ -> Append
+ -> Seq Scan on public.foo
+ Output: ROW(foo.f1), foo.f1
+ -> Foreign Scan on public.foo2
+ Output: ROW(foo2.f1), foo2.f1
+ Remote SQL: SELECT f1 FROM public.loct1
+ -> Seq Scan on public.foo foo_1
+ Output: ROW((foo_1.f1 + 3)), (foo_1.f1 + 3)
+ -> Foreign Scan on public.foo2 foo2_1
+ Output: ROW((foo2_1.f1 + 3)), (foo2_1.f1 + 3)
+ Remote SQL: SELECT f1 FROM public.loct1
-> Merge Join
Output: bar2.f1, (bar2.f2 + 100), bar2.f3, bar2.ctid, (ROW(foo.f1))
Merge Cond: (bar2.f1 = foo.f1)
***************
*** 3563,3569 ****
-> Foreign Scan on public.foo2 foo2_1
Output: ROW((foo2_1.f1 + 3)), (foo2_1.f1 + 3)
Remote SQL: SELECT f1 FROM public.loct1
! (45 rows)

update bar set f2 = f2 + 100
from
--- 3567,3573 ----
-> Foreign Scan on public.foo2 foo2_1
Output: ROW((foo2_1.f1 + 3)), (foo2_1.f1 + 3)
Remote SQL: SELECT f1 FROM public.loct1
! (49 rows)

update bar set f2 = f2 + 100
from

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